Fully enclosed electrical appliances (GIS), as a reliable power transmission and transformation equipment, have been widely applied in power systems.

Compared with the traditional open type high voltage distribution equipment, GIS has obvious advantages: compact structure, the space of the entire installation is greatly reduced: not affected by the external environment, high reliability and long maintenance cycle. Since its advent in 60s twentieth Century, GIS has developed rapidly and is playing an important role in power transmission and distribution systems.